Nissan Leaf, 2014

 

 

 Nissan Leaf, 2014

The silhouette of the world's most popular pure electric vehicle hasn't changed, but as production starts in Europe the multi-award winning Nissan LEAF has undergone a number of significant engineering enhancements.
Some of the changes have been made to improve its efficiency, some to enhance its practicality, some to enrich the ownership experience... but together they make an even more compelling case for electric vehicle ownership.

Motor and battery
The biggest single change made to New Nissan LEAF is to the powertrain - through changes that result in greater range. In the original car the battery charger and inverter was housed in the luggage area of the car behind the rear seats. Although comparatively compact, the assembly ran the full width of the trunk. As well as stealing some luggage space it meant a completely flat load floor was impossible to achieve.

The charger and inverter are now in the front of the car and integral with the electric motor itself which not only increases luggage space by 40 litres - about the size of a piece of airline 'carry-on' luggage - but also permits a flatter floor than previously when the rear seats are folded.

Though the high response AC synchronous motor develops 80kW as before, it features a number of new elements making it even more environmentally friendly and efficient. The new motor has had its intertia reduced by 5%, improving the overall efficiency of the unit.

Though the power 'stack' is now taller thanks to the inclusion of the charger and inverter with the motor, clever packaging has meant the bonnet line hasn't been changed nor has weight distribution been altered.

As before, the motor is powered by a Nissan-designed 48-module compact lithium-ion battery mounted in a single pack under the cabin area to keep the car's centre of gravity as low as possible. The battery pack is housed in a strong metal case giving extra protection in a side impact and is now assembled alongside Nissan LEAF in a new facility at Nissan's European production base in the UK.

Performance against the clock hasn changed slightly with a top speed of 144 km/h (down by 1 km/h) and 0-100 km/h taking 11.5 sec (0.4 seconds quicker than before and improvements to the car's aerodynamics, a weight loss programme and other technical changes mean the official NEDC range has risen from 175 km to 199 km.

Greater practicality is also promised by the option of an on board 6.6kW charger which allows the use of 32 amp public or home chargers.

A 32 amp post recharge a depleted battery in half the time of a typical domestic 16 amp EV socket - four hours instead of eight - but more importantly it can give a meaningful boost to a partially used battery even during a short stopover.

With 600 CHAdeMO standard quick chargers now installed across Europe, even quicker charging is available for EV drivers. A quick charger delivers 50 kW of high voltage direct current straight to the battery mean even quicker charging - it takes just 15 minutes to boost a battery from 30 to 80 per cent capacity.

Following feedback from existing Nissan LEAF owners, the car's on-board charging point has also been modified. The charger lid can now be opened remotely via the key fob or via an electric, rather than mechanical switch, in the cabin, and there's a small LED lamp within the assembly to help identify the sockets at night or in an underground car park.

Security is further enhanced by an electro-mechanical lock which fixes the cable into the socket when the battery is being charged preventing interference by third parties. On the Acenta and Tekna grades, the car can automatically notify the owner if charging is unexpectedly interrupted.

A revised warranty plan for the batteries covers against defects in materials and workmanship for five years or 100,000 kms and they are covered by a new 'State of Health' clause, which covers against excessive capacity loss for added peace of mind.

Chassis and other technical enhancements
Every Nissan LEAF built at Sunderland for the European market has a chassis package tuned by engineers at Nissan Technical Centre Europe (NTCE) in Cranfield in the UK.

The changes have been made to tailor LEAF to Europe's higher average speeds and more demanding roads. The result is a car that's more engaging to drive and yet is just as comfortable over poor road surfaces.

Damper settings, steering weight and brake performance have all been optimised for Europe. The revised dampers reduce float and help provide a more dynamic drive without adversely affecting ride comfort while to give greater feel and weight at speed the electric power steering system has been recalibrated. All of the work takes advantage of the LEAF's bespoke EV packaging, which places the battery pack and therefore the centre of gravity very low in the chassis.

The brakes are now more progressive in use and the regenerative aspect improved for better harvesting of braking energy. The system efficiency has been improved by 6 per cent to 94 per cent and the minimum speed at which energy is recovered reduced to 3 km/h from 7 km/h.

There have also been changes made to the Eco driving mode with a new 'B' setting on the transmission. B-mode increases regenerative braking during deceleration while a separate 'Eco' button on the steering wheel alters the throttle mapping to discourage harsh acceleration and thus extend the driving range. On the original LEAF the two systems worked together with increased regeneration only available in 'Eco' mode, but can now be operated independently of one another allowing drivers to benefit from greater energy harvesting under braking without having to forgo access to instant acceleration.

A new heat pump has been added to a more efficient heating and ventilation system and reduces electrical consumption when the air conditioning is in use. Air source heat pumps have been used in cutting-edge sustainable houses across Europe, but have rarely been seen in an automotive context. The heat pump works by harvesting heat energy that is present in even cold air and distributing it to the cabin. This new system improves the real world driving range, by cutting heater energy consumption by up to 70 per cent.